First post 289 rebuild question!

Ddyer2868

New Member
Nov 24, 2025
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California
I have a 68 coupe w/ 289. Built the engine about 20 years ago. Cams trashed and is currently at machine shop getting full long block rebuild. Girlfriends dad at the time had a machine shop. We put flat top 9.8:1 hyperuetectic pistons, big cam, roller tip rockers, 1.94/1.60 valves, cast heads ported and polished, performer rpm intake, 600 cfm holley double pumper. Replacing cam with Comp 262xe. The valves r too big to machine hardened seats. It was suggested to maybe run a lead additive in the gas or even just spring for leaded race fuel, maybe mixing in intervals. Has anyone else done this? Is it advised? I never ran lead before but engine only lasted about 10k miles before I think I over reved it. Please advise.
 
Budget build. I have a fastback I'm gonna put more money in to.
You can get cheapy aluminum heads on eBay for $600 about $150 to swap out the springs to match the set up, than just have your machinest fly cut the pistons if new ones don't have enough relief for a 2.02, most do these days.. Honestly the budget aluminum China heads are cheaper than paying to rebuild old iron heads these days.